1. Field of the Invention
This invention relates generally to couplings for joining rotating shafts in a drive system and more particularly to couplings with intermitting male and female components.
2. Related History
Couplings with interfitting male and female components for interconnecting rotating shafts in drive systems have been commonly used. Such couplings included a stem which projected from one of the shafts. The stem was seated in a bore of a sleeve attached to the end of the other shaft. Both the stem and the bore were of noncircular transverse cross-section so that the stem could not rotate relative to the bore.
In order to facilitate insertion and removal of the stem, the dimensions of the bore were slightly larger than those of the stem. The clearance between the bore and the stem was accompanied with certain drawbacks, however. Because of such clearance, the stem and its associated shaft did not rotate on the same axis as the bore and wobble as well as rotational play was introduced at the coupling. The wobble led to wear in the coupling itself and increased the play between the components. Coupling play in drive systems, such as, a motor drive system in a compression roller at a rolling mill, was highly undesirable. Such drive systems were exposed to intense torque shocks and coupling play and wobble resulted in accelerated wear of the entire drive system.
Attempts to reduce or eliminate play between the stem and the bore rendered assembly and the disassembly of the coupling a difficult task, since the coupling components were required to be force fitted together.
In German patent documents DE 35 43 672 and DE 35 45 651(U.S. Pat. No. 4,752,275), cylindrical shafts were interconnected to cylindrical bores in drive systems through the employment of a pressure union which comprised a bushing positioned between the shaft and the bore. Such unions required the application of large compressive forces which were necessary to prevent rotation between the components. Those unions were suited for employment in torque limiting applications since torque loads which exceeded a maximum torque resulted in slip with the torque limit dependent upon the applied pressure and other factors.